A versatile micro-mechanical tester for actin stress fibers isolated from cells

Tsubasa S. Matsui, Shinji Deguchi, Naoya Sakamoto, Toshiro Ohashi, Masaaki Sato

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

Conventional atomic force microscopy is one of the major techniques to evaluate mechanical properties of cells and subcellular components. The use of a cantilever probe for sample manipulation within the vertical plane often makes absolute positioning of the probe, subject to thermal drift, difficult. In addition, the vertical test is unable to observe changes in the sample structure responsible for mechanical behavior detected by the probe. In the present study, an alternative mechanical tester was developed that incorporated a pair of micro-needles to manipulate a sample in a project plane, allowing acquisition of the accurate probe position and entire sample image. Using a vision-based feedback control, a micro-needle driven by a piezo actuator is moved to give user-defined displacements or forces to sample. To show its usefulness and versatility, three types of viscoelastic measurements on actin stress fibers isolated from smooth muscle cells were demonstrated: strain rate-controlled tensile tests, relaxation tests and creep tests. Fluorescence imaging of the stress fibers using Qdots over the course of the measurements, obtained through multiple image detectors, was also carried out. The technique described here is useful for examining the quantitative relationship between mechanical behavior and related structural changes of biomaterials.

Original languageEnglish
Pages (from-to)401-415
Number of pages15
JournalBiorheology
Volume46
Issue number5
DOIs
Publication statusPublished - 2009 Dec 1

Keywords

  • Cytoskeleton
  • Fluorescence microscopy
  • Stress fiber
  • Tensile tester
  • Viscoelastic properties
  • Visual feedback

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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